[lib] Use the actual polymer lib file

* Includes the actual `Polymer` lib file, taken from the latest tarball.
* The file that was there before wasn't actually a copy of Polymer, and lead to these errors after trying to add it to a project.

![screen shot 2013-12-07 at 22 53 42](https://f.cloud.github.com/assets/427516/1699916/93137ace-5fd5-11e3-9988-53365d66f6b5.png)